Background: Slipped capital femoral epiphysis (SCFE) represents a relatively common hip disorder in adolescents. The present retrospective study analyzes the correlation between age, severity of the slip and physeal stability and the functional outcomes, as well as the ability to return to previous physical activity (PA) of patients surgically treated with either pining in situ (PIS) or the modified Dunn (MD) procedure (anatomical reduction of the slipped epiphysis). Methods:The present research is a retrospective observational study of patients surgically treated for SCFE from 2010 to 2015. The sample was divided into two groups: those treated with PIS and those with the MD procedure. Univariate and multivariate logistic regression analyses were performed to determine the relationship between age, Loder classification (stable/unstable), as well as Southwick slip angle (severity of the slip) to return to previous PA. Furthermore, linear regression was used to investigate the association of the above predictor variables to Oxford and Harris hip scores (HHS). Results:A total of 32 patients were identified (16 treated with PIS and 16 with the MD procedure). None of the examined predictor variables (age, Southwick slip angle, Loder classification) had statistically significant effect on the ability to return to previous PA in either the in situ or Dunn group. Univariate analysis showed that higher patients' age at the time of surgery was related to worse HHS and Oxford scores in both the PIS and MD groups. Unstable hips seem to affect unfavorably the HHS. Conclusion:The present study did not reveal any relationship between the age, degree of the Southwick slip angle, the stability of the physis, and the return to PA. Exploration of additional confounding factors are warranted to better understand the physis-related impact on the functional outcomes in both groups.